SGMICRO FT2923P

The ft2923 is a highly efficient 2x4.5W Class-G stereo audio power amplifier with automatic level control (ALC) and battery tracking AGC. It integrates dual filterless Class-D audio amplifiers with an adaptive Class-G synchronous boost regulator and operates with a range of supply voltages from 3V to 5.5V. When operating with 3.6V supply voltage, the ft2923 can deliver an output power of 4.5W per channel with 10% THD+N, or an ALC output power of 3.5W per channel with 0.3% THD+N, into a pair of 4Ω speakers. In ft2923, the power supply rails of the audio amplifiers’ output stages are internally boosted and regulated by a synchronous PWM switching regulator with two integrated power switches. The boost regulator employs current-mode PWM control with proprietary Class-G operation to regulate the boosted output voltage dynamically in response to the voltage level of the audio outputs. The ft2923 features ALC function to constantly monitor and safeguard the audio outputs against the boosted supply voltages, preventing output clipping distortion, excessive power dissipation, and speaker over-load. Once an over-level condition is detected in either channel, the ALC lowers the voltage gain of both audio amplifiers together to limit the peak audio outputs. In conjunction with ALC, as the battery supply voltage drops below a prescribed value, the battery tracking AGC lowers the voltage gain of both audio amplifiers to limit the peak audio outputs, preventing the collapse of battery voltage.

• Wide range of supply voltages from 3V to 5.5V
• Filterless Class-D audio amplifier integrated with a Class-G synchronous boost regulator
• Automatic level control to eliminate output clipping
• Battery tracking AGC to prevent battery collapse
• Soft drive mode for EMI reduction
• Maximum output power (Non-ALC Mode) (VBAT = 3.6V, ALC ≈ VBAT, THD+N = 10%) 4.5W/Ch (4Ω Load) 2.7W/Ch (8Ω Load) ALC output power (ALC Mode) (VBAT = 3.6V, ALC=NC, THD+N = 0.3%) 3.5W/Ch (4Ω Load) 2.0W/Ch (8Ω Load) Wide ALC dynamic range: 13dB
• Maximum voltage gain: 30dB
• High efficiency: 76% (VBAT = 3.6V, 4Ω Load, Po = 2W/Ch, both channels driven)
• Volume fade-in and fade-out
• Under-voltage lockout protection
• Auto-recovering over-current & short-circuit protection
• Thermal over-load protection
• Available in TSSOP-28L package

• Blue Tooth Speakers
• Portable Audio Decks
• Consumer Audio Electronics